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For Susquehanna's smallmouth bass, a tiny sign of hope amid the gloom

spotted bass.jpg

A smallmouth bass collected from the Susquehanna River near Selinsgrove displays the black spots that have anglers concerned. Many of the same harsh environmental factors that stress adult fish like this one contribute to the low survival rates among young of the year smallmouths, which is keeping the fish from recovering to historic levels.
(PA FISH & BOAT COMMISSION PHOTO)

Long-time fisherman John Beistline noted a paradox -- as the Susquehanna's water has gotten clearer, the fishing has gotten worse.

What’s causing the sorry state of the Susquehanna River’s smallmouth bass is still a complicated mystery with many likely causes, but there’s a tiny ray of encouraging news amid the gloom.

That’s the message Fish and Boat Commission biologist Geoffrey Smith delivered to a group of about 50 during a talk at Wildwood Park Tuesday night.

Smallmouth bass are still being stressed by a “perfect storm” of harmful factors that keep young of the year fish from reaching adulthood, Smith said.

Adverse river temperatures, pollution that stimulates algae growth, and chemical contaminants all combine to make hostile conditions for the young fish to survive.

“No single factor seems to be causing the problem,” Smith told the group.

“There are decent numbers of large fish,” Smith explained, but drastically low numbers of very young fish.

The most critical factor – river flow in June, when young of the year smallmouth need shallow, warm water – has been favorable, but their numbers have not rebounded as expected. It takes five to six years for a smallmouth to reach the 15-inch length that anglers covet.

Among the suspects in the biologists’ detective work is a slew of contaminants: 15 PCB-related compounds, 13 flame retardants, 14 organochlorine chemicals and nine other pesticides, plus triclosan, used in anti-bacterial soap.

Endocrine-disrupting chemicals seem to be having serious impact. In samples that were studied, female cell characteristics showed up in almost all the male fish, Smith said — far more than the naturally-occurring rate.

All those chemicals may also help make the fish more vulnerable to parasites. “We found heavy parasite loads in fish only 60 to 70 days old. That’s very unusual,” Smith said. The parasites offer a way for harmful bacteria to penetrate the fish’s skin, while also compromising their immune system.

On the brighter side, surveys in 2013 found surprising numbers of smallmouth bass in the 7-to-8-inch range, Smith noted. That’s an encouraging development, he said, but it’s too early to say it heralds any kind of turnaround. The new counts are still below long-term averages, and in any event, he wants to see similar results for a few more years.

After Smith’s talk, long-time fisherman John Beistline noted a paradox – as the Susquehanna’s waters has gotten clearer, the fishing has gotten worse. In his youth, it was possible to catch your limit of fish every night, but “over the years, there’s less and less and less fish,” he said.

“When I was a kid, the water was never as crystal clear as it is now.” He went snorkeling two years ago off Fort Hunter, where he saw very few fish.

Retired state fish biologist Larry Jackson collected much of the early data on the Susquehanna’s smallmouth bass. Chatting with Smith afterward, he said the situation today is “so painful” compared to times past.

“You had to see it. You had to fish it,” to understand the difference, Jackson told Smith.

“Several factors are causing young of the year mortality,” Smith said after his talk. “The answer remains somewhat out of reach.” But, as he told the audience during his talk, it’s pretty clear that the river needs to go on a “pollution diet.”

Matt Zencey is Deputy Opinion Editor of PennLive and The Patriot-News. Email mzencey@pennlive.com and on Twitter @MattZencey.